French authorities said Friday that face masks will again be required in all public spaces indoors and out in a southern region bordering Spain, after Covid infections soared this week because of the more infectious Delta variant.

Alcohol drinking will also be prohibited outdoors in the Pyrenees-Orientales department on the Mediterranean coast just north of Spain, which is also seeing a surge in Delta cases.

The masks will not be required however on beaches or in wide open spaces such as mountain trails, regional authorities said in a statement.

"More measures could be announced depending on the evolution of health indications and pressure on the hospital system," the prefecture said.

France is hoping to avoid a fourth wave of Covid-19 cases that could overwhelm hospitals and again lead to painful lockdowns or other restrictions.

The Pyrenees-Orientales department now has the highest Covid incident rate in France at 257 per 100,000 people, up from 130 on Monday -- well above the alert level of 50.

Rates are even higher in neighbouring Catalonia and elsewhere in Spain, and French officials have urged people not to cross the border for holidays.

Overall in France the incident rate stands at 40, according to the health ministry, but daily case numbers have been rising rapidly as the Delta variant spreads.

On Monday, President Emmanuel Macron said vaccinations would now be mandatory for healthcare and retirement home workers, many of whom remain reluctant or outright opposed to the jabs.

Starting next week, proof of vaccination or a negative Covid test will be required for theatres, cinemas, music festivals and amusement parks.

In August the "health pass" will also be required to enter any restaurant, cafes, bars or shopping centres, or for long train journeys.